The present invention relates to the an apparatus for atomizing a sample for flameless atomic absorption analysis, atomic fluorescence analysis and Zeeman atomic absorption analysis (the apparatus will be hereinafter referred to as "atomizer"), and more particularly to an atomizer, using a cuvette made of carbon, such as graphite, tungsten, tantalum, etc. as a heating material.
A graphite atomizer using a graphite tubular cuvette will be explained below as a typical atomizer.
The graphite atomizer is to perform atomic absorption analysis by supplying a large amount of electric current to a graphite tubular cuvette from a pair of electrodes connected to the cuvette, thereby heating the cuvette and a sample introduced into the cuvette, and decomposing and atomizing the sample, and passing a light from a source of atomic spectra through the atomized vapor formed in the cuvette.
When polar pieces (magnet) are provided at both sides of the graphite tubular cuvette to apply a magnetic field to the atomized sample, the absorption spectral lines are split owing to Zeeman effect. This provides a basic structure of Zeeman atomic absorption analysis utilizing the Zeeman effect, and the Zeeman atomic absorption spectrophotometer based thereon is disclosed in detail in U.S. Pat. No. 4,202,628, and its basic structure and the principle of measurement according to it will be explained below, referring to FIGS. 1 and 2.
In FIG. 1, a light source 1 emits light with a single wavelength including two polarizing components P.sub.V and P.sub.M perpendicular to each other. A detector 2 is disposed on the optical path of the light source to receive the light. An atomizer 3 including a graphite tubular cuvette is disposed on the optical path between the light source 1 and the detector 2, and polar pieces 4 and 4' are provided at both sides of the cuvette to produce a magnetic field. A spectrometer 5 is disposed on the optical path between the atomizer 3 and the detector 2 to spectroscopically analyze the light from the atomizer 3. A polarization discriminator 6 is disposed on the optical path between the spectrometer 5 and the detector 2, and discriminates the two orthogonal polarizing components P.sub.V and P.sub.H from the light source 1.
The light having the two polarizing components P.sub.V and P.sub.H perpendicular to each other passes through the atomized sample in the atomizer 3 to produce absorption spectral lines, which are divided into three components as shown in FIG. 2 by the magnetic field H of polar pieces 4 and 4'. The three components are the first absorption spectral line component 21 having substantially a wavelength .lambda..sub.R of light 20 emitted from the light source 1, and the second and third absorption spectral line components 22 and 23 of wave length .lambda..sub.R +.DELTA..lambda. and .lambda..sub.R -.DELTA..lambda., respectively, spaced apart by .+-..DELTA..lambda. from the wavelength .lambda..sub.R of the first absorption spectral line component 21. The first absorption component 21 is characteristically absorbed only by the polarizing component with an oscillation surface 24 parallel to the magnetic field H, and the second and third absorption components 22 and 23 are, on the other hand, characteristically absorbed only by the polarizing component with oscillation surfaces 25 and 26 perpendicular to the magnetic field H. The light from the light source 1 includes the polarizing component P.sub.V with an oscillation surface orthogonal to the magnetic field H, and the polarizing component P.sub.H having an oscillating surface parallel to the magnetic field H. Thus, only the component P.sub.H is absorbed by the first absorption component 21, and the component P.sub.V is not absorbed by the first absorption component 21 or by the second and third absorption components 22 and 23, because the component P.sub.H coincides with the first absorption component 21 in absorption wavelength position and absorption oscillation surface, while the component P.sub.V coincides with the first absorption component 21 in absorption wavelength position, and not in the absorption oscillation surface, and further coincides with the second and third lines 22 and 23 in absorption oscillation surface and not in the absorption wavelength position. That is, the component P.sub.V is not absorbed in any case. The component P.sub.H, as absorbed by the first absorption component 21 and the component P.sub.V, as not absorbed by any of the three absorption components are introduced into the spectrometer 5. The two components P.sub.V and P.sub.H selected in the spectrometer 5 are discriminated in the polarization discriminator 6 simultaneously or in a time-sharing manner. The two polarizing components are emitted into two directions from the discriminator 6 and led to detectors 2 and 2', respectively. A signal difference is measured from the two polarizing components in the detectors 2 and 2' to provide only the atomic absorption without any influence of background absorption.
The cuvette employed in such an analyzer is disclosed in U.S. Pat. Nos. 4,202,628 and 4,022,530.
The U.S. Pat. No. 4,202,628 discloses prevention of condensation or recombination of atomized sample on the cuvette wall by using a cuvette of special form, and the U.S. Pat. No. 4,022,530 discloses supporting of a tubular cuvette under pressure by means of spring washers.